Process of making superior sugar.



- UNITED STA ES PATENT oFFioE.

N IELs BREINHOLT BACI-I, or MODJ'OHERTO, Java.

PROCESS OF MAKING SUPERIOR SUGAR .1 $04,095 No Drawing.

of the invention, such as will enable others skilled in the art towhich it appertains to make and use the same.

In the Tropics sugar-manufacture. from cane-sugar is up till now carried out as briefly follows: The so-called raw-juice from cane-sugar mills is first purified by adding lime-milk to it, which is neutrals ized with carbonic acid or sulfur dioxid after having produced its reaction. According to one or the other of these acids beingused, the process is called carbonatation or sulfitation. After treating this socalled thin-juice to neutral reaction it is allowed to settle, after which the fpurejuice is drained off and the remaining quantity is let to settle a second time. The

settled juice, called dirty-juice is returned to the raw-juice, while the purejuice is evaporated until it is reduced to about one fourth of its original volume and let to settle, after which it is sulfited to marked acid reaction and is then fit for fur-" ther sugar manufacture.

The oarbonationand sulfitation-processes have advantages and drawbacks. The ad-' vantage of carbonation is obtaining a whiter, more sugar, notwithstanding the decomposition of glucose taking place with this method. The drawback of this process is the high first costs for acquiring the necessary apparatus.

The invention relates to manufacturing by means of the sulfitation-process superior sugars which are at least as good and as conservable as those obtained by the carbonation-method, without raising the initial or working costs. Different proposals have already been made in this respect and will be briefly mentioned here in order to explain clearly the new process. Up till now the quantity of lime-milk added to the raw-juice for purifying same varied from 6 to 10 liters (15 B.) per 1000 liters of juice. This lime-milk is mixed with the juice or, in case of the continuous process, before the sulfiters, the time of reaction Specification of Letters Patent.

- chemicals.

Patented July 21, 1914.

Application filed August 4, 1913. Serial No. (82,903.

I being consequently very short. After a twofold settlement thev thin-juice is evaporated to thick-juice which is boiled and allowed to settle in general without the addition of This results in a rather lightcolored, but dull thick-juice, while nice and conservable sugars require in the first place a clear, sparkling thick-juice.

The proposed improvements related to: 1. Addition of chemicals to. the. thin-juice or the thick-juice, in order to raise their settling and filtering capacities. 2. Filtration of the thinand thick-juices. 3. Larger addition of lime. 4. Heating of the juice before or during the sulfitation.

Under step'l. Thechemicals added to the uice were generally for the thin-juice:

soluble phosphates, for the thick-juice:

with phosphoric acid or with phosphates may produce in many cases a thick-juice which is somewhat clearer, part of the finely divided organic substances being carried away by the phosphate of lime. -.However a much better thick-juice is not obtained. nor

is it always possible, to filter successfully the thick-juice treated in this way.

Under step 2.-Filtration of the thin-juice in sulfitation-works is not very logical, as

upon boiling and concentrating the thinjuice to thick-juice a great quantity of inorganic and principally organic substances not being able to remain any longer in solution will separate therefrom and are very difficult to be settled or filtered. Furthermore filtration of the pure thin-juice is very diflicult, the filtered juice being dull and not very much better than the unfiltered pure-juice.

A better result than b the means mentioned under 1 and 2 is o tained by raising the lime-addition as indicated under 3.

' This results in a more intensive juice-purification and a better settling. The thinjuice as well as-the thick-juice are slightly improved thereby, but a clear, sparkling thick-juice is never obtained in sulfitationworks, even by an addition of 12-15 liters of lime per 1000 liters of juice. During the evaporation a precipitation of organic substances always takes place which does not settle down in the thick-juice and cannot be taken aWay by-filtration. Furthermore rather large quantities of the deposit are always carried away when draining oil the pure thin-juice, principally of those substances of the thin-juice which settle most diflicultly. These substances consequently joint the thick-juice and are extremely difficult to be removed from it by Settlementor filtration.

The proposal mentioned under 4 seemed to be important enough to submit it to an exhaustive trial. The result of this examination, which cannot be described in detail, was the following one: Upon heating the juice to 60 C. after the addition of lime a slight decomposition of glucose occurred which is, however, of but little importance for the manufacture of conservable sugars and which can be prevented by heating not before, but during the sulfitation. It is still better to heat the juice before the addition of lime and sulfite it immediately afterward. In this way decomposition of glucose by lime depending more upon the time than upon the temperature does not take place as now highest temperature and highest alkalinity coincide, the juice-purification being, therefore, most intensive. However, the above described, methods do not'permit of obtaining a perfectly clear and sparkling thick-juice.

Without entering into extraordinarily large and costly lime-additions, filtration of thinjuice and thick-juice gives but little result and a rather large lime-addition (10 liters), combined with heating the juice before adding the lime, constitute merely a means of obtaining a slightly better juice-purification, never resulting, however, in a perfectly clear thick-juice, principally because the juicepurification is not yet intensive enough, but partly too because the clearness of the thickjuice depends on two or three settlements, the last of which generally must be a failure because of the great density of the thickjuice and the low specific weightof the organic substances polluting it. A more intensive juice-purification is only to be obtained by improving the three principal conditions, under which the reaction takes place, namely time, temperature and concentration. At the first sight it seems difficult to give a prescription for purifying cane-juices containing much glucose so that these three factors are utilized as well as possible without obtaining an important decomposition of glucose and darkly colored juices. However, a great number of trials in laboratory and workshop proved that the following new juice-purifying method takes as much as possible into consideration the above mentioned features, which are important for an intensive juice-purification without the onerous glucose-decomposition taking place or any other drawback adhering to this method.

for each 1000 liters of thick-juice four times the remaining quantity per 1000 liters thinjuice will be available, while moreover the juice-concentration and consequently the in tensity of the purification are much higher. For instance 25-4 liters of lime-milk are required for neutralizing 1000 liters of thinjuice, while for a good-settlement generally an excess of 2-3 liters of milklime will do,

totaling up to about 6 liters. ith the old method, where the whole juice-purification takes place in the preliminary works, a still higher lime-addition is applied in order to obtain at the time less dull thinand thickjuices, so that in most well-conducted works 8 10 liters of lime-milk or more are added per 1000 liters of juice. According to the new process only 6 liters of lime are e. 9. added to the thin-juice for the purification,

, and easy settlement of the raw-juice, so that a quantity of lime of (106) 4=16 liters remains per 1000 liters thick-juice in case the concentration is 4 :1. a

A number of raw-juice samples, taken in same color-effect. A low percentage of lime points to intensive juice-purification.

Liquid-col- Milligrams umn in mil- CaO per limeters. liter.

Thinnice 1 100 400 Thin-iuice2...... 480 Thickduice 1 85 1285 Thick-juice 2 68 1162 The numbers prove therefore that an efficient juice-purification is obtained by the new method. The light color and the low lime-percentage of the thick-juice indicate that there isno question about any perceptible glucose-decomposition.

Continued trials have proved that it is to be recommended to add the lime as early as possible to the raw-juice, also for preventing the acidification of the raw-juice, a lighter color and a clearer juice equally resulting therefrom. It is not at all to. be

- thick-j uice being3 glucose-decomposition does not take place,- the necessary time failing because of the sulfitation following directly on the limeaddition. The filtration of the thick-juice as obtained by the new method, takes half the time of that of the old process, which directly proves that this juice-purification is a better one. limo also influences favorably the'removal of fast color substances, which is very important for the color and conservability of the sugar. The above-mentioned favorable results have been confirmed by applying the new process on a large scale. Treatment at a high temperature has, however, the drawback of alkaline glucose-decomposition preventing the new process from reaching its maximum efficiency. Such glucose-decomposition is more intensive according to the lime-addition or the temperature'o-f the higher, while a temperature above 60 is not tolbe admitted for the above-described process, though this would be very desirable for juice-purification and filtration. At the first sight this seemed to be inevitable as up till now juicepurification in white-sugar works was considered to essentially take place in the following way: Lime-addition neutralizes in the first place the acids of the juice and the excess of lime precipitates more or lessv perfectly the organic substances of the sugarjuice (color, pectinand gum-substances) after which the excess of lime is neutralized by SO or C0,. The more intensive juicepurification of carbonation works was therefore attributed to the higher alkalinity of the raw-juice after lime-addition and the general conviction was that good juice-purification required a high initial alkalinity of the juice. For this reason larger lime-additions were often used in sulfitation-works and in professional literature it was always. indicated that lime should be added at once in order to obtain the advantage of high initial alkalinity. However, the applicant gradually came to the supposition that this theory ofjuice-purification was not the right one and accurate laboratory-trials confirmed this. Some of these trials will only briefly be mentioned here.

A sample of thick-juice was divided into two equal parts of exactl 0.5 liter. After heating sample 1 to 60 10 cm of limemilk was added and after mixing well the sample was sulfited to neutral reaction with an SO -solution. For arriving at the neuties of lime and S0 had been added to Treating thick-juice with.

tral point- 225 cm of this SO -solution were required.

To sample 2 first 22.5 cm of SO -solution were added and afterward 10 cm of limemilk. The reaction of No. 2 after mixing. was totally neutral as expected.

y The difference between the two samples consisted in the fact that sample 1 had been purified in the ordinary and generally known way, while exactly, the same quantisample 2 the addition of lime, however, taking place in the latter case after the S0 addition. Sample 2 never had effectively been alkaline and it was to be expected, therefore, in relation with the above juicepurification theory accepted up till then, that no juice-purification had taken place with this sample. Sample 1 was therefore expected to consist ,of thick-juice, precipitated organic substances and sulfite of lime, sample 2 on the contrary of thick-juice, the organic substancesof which were not precipitated, and sulfite of lime. Investigating into the matter more closely, however, made clear that both samples had been purified one as well as-the other, while both had the same light color after filtration, were filtered with the same velocity and contained finally the same quantity of lime too. This was, indeed, very remarkable, considering the totally abnormal way of treating sample 2 with S0 and lime. The trials were repeated with thick-juice as well as with raw-juice and ,syrups,.always givingv the same result, proving that the theory concerning the favorable influence of the maximum juice alkalinity on neutralization is not exact and that juice-purification is more of a physical than of a chemical nature. Precipitating the organic substances therefore takes, probably place in the moment, that lime and S0 react oneach other, i.;e. while the sulfite of lime is in statu nascemii and the more sulfite of lime is formed (in accordance with more .110 lime having been added) the better a juieepurification is obtained while it is totally indifferent if lime or S0 is added first. This discovery was'of great importance for the application of the above-mentioned sample 2 at a temperature of about 80 (1., S0 and lime being fractionally added in order to prevent alkaline reaction.

The same favorable results Were obtained by treating raw-juice and syrups.

What I claim as my invention and desire. to secure by Letters Patent is:

1. In the method of making White cane sugar, the process which, comprises liming and sulfiting the thin juice sufiiciently to clarify it, filtering the juice, concentrating the filtrate to thick juice, liming and sulfiting the thick juice and filtering the same.

The results of the trial Were the follow-- being neutral after said action, and the quantity of lime less than that required for complete liming of the juice, filtering the juice, concentrating the thin juice to thick juice and forming sulfite of lime Within the thick juice and filtering thejuice, the total quantity of lime for both thin and thick juices being less than the normal quantity of lime required for liming. In testimony that I claim the foregoing as my invention, I have signed my name in presence of tWo subscribing Witnesses.

NIELS BREINHOLT EACH.

Witnesses N; SCHMIDT, T. MEDINA. 

